This invention relates to the field of photography. More particularly, it is related to a mount for transparent originals in such photographic devices wherein any photographic work is executed from a transparent original. Examples of such work is photographic imaging, reproduction, especially on optical benches, and production of colour separations and other selections, enlarged prints, screen technique prints, etc.
Original or negative mounts known until now usually comprise two glass plates fixed on a support; the transparent original or negative is retained between these parallel glass plates. Such original mounts have numerous disadvantages. For example, the glass plates must always thoroughly be cleaned before the introduction of an original since any speck would result in defective reproductions, screen prints, separations etc. which have been made from an original placed between dirty surfaces of glass plates. It must be noted that cleaning of glass plates usually creates electrostatic charges which tend to attract dust so that the cleaning results are always doubtful.
Furthermore, the fact that an original is placed between two glass plates does not permit the operator to replace the original exactly at the same location when the original had to be removed from between the plates, for example in order to execute corrections or retouches. Every time an original is removed from the original mount, the entire photographic installation must be completely readjusted.
Another disadvantage of conventional original mounts is the fact that image distortions or defects may occur due to the refraction and reflection of light on the plane-parallel glass plates. In addition thereto, it is known that glass is very difficult to be made without defects like inclusions, streaks, etc. which also cause image defects.
A further disadvantage of the original mounts of known glass plate type is the fact that all series work using more than one original, is impossible without intermediate adjustment even if each original has been prepared in its own particular mount or frame.